Wallace Line

Wallace Line

Why is it in the News?

In the 19th century, Alfred Wallace noticed a distinct change in the species composition between Asia and Australia. This observation later led to the identification of the Wallace Line.

What is the Wallace Line?

• About: The Wallace Line is an imaginary boundary that separates the distinct faunal regions of Asia and Australia. It represents a significant biogeographical division with noticeable differences in species on either side.
• Geographical Location: The line runs through the Makassar Strait, which lies between the eastern coast of Borneo and the western coast of Sulawesi. It also extends between Bali and Lombok, separating the Sunda and Sahul continental shelves.

Species Distribution:

• West of the Wallace Line (including Bali, Borneo, Java, and mainland Asia): The fauna here consists of species such as monkeys, apes, rhinos, squirrels, tigers, and hornbills, which are typical of the Asian ecosystem.
• East of the Wallace Line (including Lombok, Sulawesi, Timor, and Australia): The fauna includes species like tree kangaroos, cockatoos, and honeyeaters, characteristic of the Australian ecosystem.

Wallacea Region:

• This region, located between the Wallace Line and the Weber Line (another faunal boundary to the east), includes islands like Sulawesi, Flores, Lombok, and Timor. These isolated Wallacean islands have lower biodiversity compared to the nearby continents but are home to unique species such as the Komodo dragon, babirusa, and giant bees.
• Sulawesi is notable for having both Asian species, such as tarsiers and anoas, as well as Australian marsupials like the dwarf cuscus.

Reason for Formation:

• Continental Drift: About 85 million years ago, Australia separated from Antarctica and moved northward, isolating species and encouraging independent evolution.
• Deep Oceanic Barriers: The Wallace Line aligns with deep waters like the Makassar Strait, which remained submerged during ice ages, preventing the movement of species between Asia and Australia.
• Geological Climate Change: Species from both Asia and Australia, adapted to their respective climates, found it difficult to migrate across the Wallace Line.

UPSC Civil Services Examination, Previous Year Question (PYQ)

Prelims

• Q. Which one of the following pairs of islands is separated from each other by the ‘Ten Degree Channel’? (2014)
  (a) Andaman and Nicobar
  (b) Nicobar and Sumatra
  (c) Maldives and Lakshadweep
  (d) Sumatra and Java
  Ans: (a)

• Q. Consider the following statements: (2010)
  Biodiversity hotspots are located only in tropical regions.
  India has four biodiversity hotspots: Eastern Himalayas, Western Himalayas, Western Ghats, and Andaman and Nicobar Islands.
  Which of the statements given above is/are correct?
  (a) 1 only
  (b) 2 only
  (c) Both 1 and 2
  (d) Neither 1 nor 2
  Ans: (d)

Tags : UPSC 2025 current affairs preparation, UPSC current affairs January 2025, UPSC 2025 daily current affairs, Best sources for UPSC current affairs 2025, UPSC 2025 current affairs for prelims, UPSC 2025 current affairs for mains, Important current affairs for UPSC 2025, UPSC current affairs strategy 2025, UPSC 2025 current affairs notes, UPSC current affairs PDF 2025, Current affairs for UPSC 2025 preparation, UPSC 2025 current affairs online classes, UPSC current affairs quiz 2025, How to study current affairs for UPSC 2025, UPSC 2025 current affairs magazines, Current affairs for UPSC 2025 prelims and mains, Current affairs updates for UPSC 2025, UPSC 2025 current affairs analysis, Current affairs for UPSC 2025 PDF download, UPSC 2025 current affairs important topics, UPSC reading comprehension tips, UPSC reading comprehension practice papers,  UPSC reading comprehension strategy, UPSC reading comprehension questions,  UPSC reading comprehension exercises,  How to improve reading comprehension for UPSC, UPSC reading comprehension question papers PDF,  Important reading comprehension topics for UPSC, UPSC reading comprehension passage solutions, UPSC reading comprehension best books, UPSC GS reading comprehension examples, UPSC Prelims reading comprehension preparation,